GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]

Building a morphogen gradient by simple diffusion in a growing plant leaf

In an article published in Biophysical Journal, the team of Associate Professor Kensuke Kawade at the Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology in Japan showed that a transcriptional co-activator ANGUSTIFOLIA3 (AN3) forms a signaling gradient along the leaf proximal-to-distal axis to determine cell-proliferation domain. In particular, by experimental and theoretical approaches, they demonstrated that pure diffusion in a growing tissue is sufficient to explain the AN3 gradient formation. This work provides evidence that the diffusion-based model of morphogen is viable in developmental patterning of multicellular organisms.

Spatial gradient of signaling molecules is critical for establishing developmental patterns of multicellular organisms. Around half a century ago, a seminal work proposed a theory that pure diffusion of signaling molecules from a restricted source may explain the establishment of such tissue-scale gradients (Crick, 1970). Despite the prominence of this diffusion-based model in development, quantitative studies, largely performed in animals, have not yet demonstrated this simple mechanism in multicellular tissues.

Dr. Kawade's team at OIBB/NIBB, in collaboration with scientists in the Institut Jacques Monod (France), Rikkyo University (Japan) and University of Tokyo (Japan), solved a long-standing argument of the diffusion-based model for morphogen gradient formation. They measured molecular transport through plasmodesmata, a unique cellular channel in plants directly connecting neighboring cells, by trans-scale FRAP (Fluorescence Recovery After Photobleaching) assays. This analyses revealed biophysical properties of diffusive molecular transport through plasmodesmata. Based on this diffusion-based framework, they succeeded in demonstrating that the AN3 gradient could be achieved solely by pure diffusion process through plasmodesmata in developing leaf primordia. Because the AN3 signaling gradient corresponds to the cell-proliferation domain, this study can explain how spatial and temporal dynamics of cell proliferation, and therefore tissue growth, is regulated during leaf development.

These discoveries provide a significant step forward in our understanding of how the simple biophysical phenomena 'diffusion' governs developmental patterning in multicellular organisms.

Read the paper: Spatially different tissue-scale diffusivity shapes ANGUSTIFOLIA3 signaling gradient in growing leaves.

Article source: National Institutes of Natural Sciences.

Image credit: National Institute for Basic Biology


Algae have land genes

500 million years ago, the first plants living in water took to land. The genetic adaptations associated with this transition can already be recognized in the genome of Chara braunii, a species of freshwater algae. An international research team headed by Marburg biologist Stefan Rensing reports on this in the journal Cell.

Rice plants evolve to adapt to flooding

Although water is essential for plant growth, excessive amounts can waterlog and kill a plant. In South and Southeast Asia, where periodic flooding occurs during the rainy season, the water depth can reach several meters for many months.

Invasive plants adapt to new environments, study finds

Invasive plants have the ability to adapt to new environments - and even behave like a native species, according to University of Stirling research.